The most commonly used handguns are revolvers and semi-automatic pistols. There are advantages and disadvantages associated with both of these types of firearms.
The semi-automatic pistol is loaded with a clip-type of magazine. This magazine holds more rounds of ammunition than the cylinder of the typical revolver and is easier to load and unload. However, for repeated fire, a sequence of cartridges must be fed into the same chamber, then ejected, which often results in a jammed mechanism. The semi-automatic may be "single action" or "double action". The "single-action" semi-automatic is normally carried "cocked and locked" by law enforcement personnel. This means that the hammer mechanism is cocked and ready to fire at the slightest trigger pressure, but the hammer is held in place by an exterior safety device, which must be released in order to operate the weapon. When ready to fire, the hammer and magazine springs of the "single-action" semi-automatic are under constant compression. As a result, the long term reliability of this weapon is decreased, and additional maintenance and repair are required. In contrast, the "double-action" semi-automatic can be fired without releasing a safety mechanism, but requires a greater trigger pressure for the first round than for succeeding rounds, in turn requiring an adjustment by the shooter. Moreover, the magazine spring of a "double-action" semi-automatic is also under constant compression.
Mechanically, the revolver is simpler than the semi-automatic pistol. In addition, the revolver mechanisms are unstressed when ready to fire. As a result, the revolver is easier to operate and maintain, and is less prone to accidental discharge and jamming, than the semi-automatic pistol. For these reasons, the revolver is preferred to the semi-automatic by most law enforcement agencies.
A major disadvantage of the revolver is the length of time needed for reloading. This disadvantage has been partially alleviated by the development of the "speed loader." Typically, the commercially available speed loader maintains a full reload of fresh cartridges in an arrangement which conforms to the configuration of the cylinder bores. The speed loader thereby allows a full complement of cartridges to be transferred to the cylinder simultaneously, rather than individually.
However, there are disadvantages associated with the use of the speed loader. First, when a law enforcement officer using the speed loader is under fire, the officer's eyes must be taken off of the assailant in order to align the speed loader with the cylinder in order to reload. During the reloading, the assailant may maneuver and thereby gain a strategic advantage. Second, the proper use of a speed loader requires considerable training and practice. Even an expert in the use of the speed loader may require at least five seconds to accomplish this task. Third, many speed loaders fail to adequately protect the ammunition while in storage. Thus, if the speed loader were accidently dropped, the ammunition may become damaged or misaligned.
In the known prior art, revolver cylinders have been permanently mounted to the revolver frame by means of a crane pivot or linkage. These crane mechanisms may fail after a period of time due to the relatively-high impact loads incurred during firing of the revolver. Additionally, in the known prior art, the ejection and replacement means for such cylinders are cumbersome and time consuming, and are intended solely for maintenance rather than reloading.